The disclosure relates to a piston pump for a hydraulic vehicle brake system.
Such piston pumps are used to convey brake fluid in slip-controlled hydraulic vehicle brake systems, they are often also referred to as recirculating pumps. They have a pump piston which is arranged displaceably in a pump bore and can be driven by an eccentric into a to and fro stroke movement in order to convey brake fluid in the vehicle brake system in a manner known per se. The eccentric is typically arranged radially with respect to the pump piston and an eccentric-side face end of the pump piston bears against a circumference of the rotationally drivable eccentric. Several piston pumps can be driven jointly by one eccentric. Two piston pumps—one piston pump for each brake circuit of a dual circuit vehicle brake system—are often arranged opposite one another with the eccentric between them. The piston pumps are also understood as pump elements of such a multi-piston pump. Valves, typically non-return valves, of which one forms an inlet valve and another forms an outlet valve, control a throughflow direction of a pump flow through the piston pump, wherein pump flow refers to a throughflow of the piston pump generated by the stroke movement of the pump piston.
Published patent application DE 10 2011 079 876 A1 discloses such a piston pump for a hydraulic vehicle brake system which has a perforated disk as a dynamic throttle in a pump outlet. An inner edge of the perforated disk is fixed, an outer edge lies with a prestress on an annular support. A pump flow generates a pressure differential at the perforated hole which forms the throttle and which lifts the outer edge of the perforated disk off from the support so that the pump flow flows around the outer edge of the perforated disk. The perforated disk additionally has a small throttle hole between the inner edge and the outer edge through which the pump flow flows as a static throttle irrespective of whether the outer edge of the perforated disk which forms the throttle lies on the support and is lifted off from the support by the pump flow.